I used Supercopier before, it works very well but is always in memory so it use some RAM even on idle, now i switched to Teracopy that have the same options but it use RAM only during the copy.
The advantage of those utility is the many options they have (like pause/resume options during copy/cut, etc...)
I strongly recommend Teracopy.
i will try Fastcopy and Extremecopy then send feedback.